Over the years, cross-cultural studies of mental disorders have reported a
number of culture-specific disorders, and the rates of specific mental
disorders have differed considerably across epidemiological surveys. This
article attempts to address the assertion that the basic psychopathology is
universal and that cross-cultural differences have derived mainly from
culture-specific illness behaviour. Furthermore, it is argued that there is no
solid evidence for a real difference in the prevalence of common psychiatric
disorders across cultures. Although there is some progress, the fundamental
problem across these studies over the development of cross-culturally
comparable case definition and standardised clinical interviews is still
awaiting a better solution.

CULTURE-SPECIFIC DISORDERS

The concept of ‘emic’ has been proposed to describe
culture-specific psychopathology, in contrast to the concept of ‘
etic’, which sees psychopathology as universal and sociocultural
influences as pathoplastic in nature
(Murphy, 1982). Researchers
such as Yap (1965) argued that
culture-specific disorders reported from non-Western societies could be
regarded as pathoplastic variants of disorders commonly observed by Western
psychiatrists. Many patients with such syndromes were found to have suffered
mainly from anxiety and depressive disorders (e.g.
Kleinman & Kleinman,
1985). Moreover, some of these disorders were found later to have
existed in more than one culture, including Western (e.g.
Kendall & Jenkins,
1987).

The role of sociocultural factors in these emic disorders is by no means
confined only to their pathoplastic shaping of common symptoms. In a study of
koro epidemics in Guangdong, China, a strong folk belief of koro was
speculated to have acted upon specific personal vulnerability (low
intelligence) in times of major social crises to generate the epidemics
(Tseng et al, 1992).
From the epidemiological point of view, such belief is a kind of morbid
suggestion acting as the transmitting agent for communicable mental disorders
(Shepherd, 1978).

Another important role for sociocultural factors in such emic disorders is
their influence on illness behaviour. In the case of koro, those who suffered
from it (falsely) perceived a shrinkage of the penis and interpreted its cause
as the female fox spirit come to collect young men's penises, resulting in
death. The victims thus reacted with panic attacks and sought help from their
family members and neighbours to rescue them by any means. It is most likely
that the specific features of these emic disorders have derived mainly from
culture-specific illness behaviour rather than from any emic psychopathology
of common mental disorders.

MANIFESTATION OF SYMPTOMS

There is a fundamental difference between subjective complaint and symptom
manifestation. Subjective complaint is a kind of illness behaviour that
concerns how an individual perceives, interprets and reacts to the
psychological discomfort that he or she may have, whereas symptom
manifestation is the psychiatrist's judgement on a patient's condition through
clinical observation and interview (Cheng,
1989; Brugha et al,
1999a).

This difference may have an important implication on cross-cultural studies
of psychological symptoms upon which diagnoses are made. The rate of any
symptom detected by recording the patient's self-report presumably would be
different from that of the clinical symptoms assessed by a standardised
diagnostic interview. In fact, what has been obtained from self-report is the
subjective complaint rather than the objective symptom, which can be assessed
only clinically. For instance, somatisation has been reported to be a
characteristic feature among non-Western patients with depression (e.g.
World Health Organization,
1983). Researchers such as Kirmayer
(1984), however, stated that
somatisation has been found around the world.

It is probable that psychologically disturbed patients in less-developed
societies with limited knowledge of mental disorders interpret their illness
as being physical in origin and therefore complain of somatic discomforts to
their doctors more often than their Western counterparts. However, the
frequencies of somatic symptoms among patients with depression and community
respondents have been reported to be very similar between East and West when a
detailed psychiatric interview was carried out
(Cheng, 1989).

It follows that if the diagnosis of somatisation disorder is based only on
the exclusive self-reporting of somatic complaints, then this is most likely a
diagnosis of illness behaviour rather than of a disorder, an exercise similar
to that applied to other emic disorders. Because somatic symptoms are
frequently an important part of psychiatric disorders, the diagnosis of
somatisation disorder should be given only when primary psychological symptoms
are not found in spite of adequate standardised clinical assessment.

FREQUENCIES OF SPECIFIC DISORDERS

One may infer that cross-cultural comparisons using identical case
definition and standardised diagnostic interviews as case-finding instruments
are likely to produce the most useful results. There have been several such
studies reported in the past two decades, employing either semi-structured
clinical interview (such as the European study on old-age depression with the
Geriatric Mental State (GMS) schedule and the EURO-Depression scale (EURO-D))
or fully structured lay-interviews (such as the Diagnostic Interview Schedule
(DIS) and Composite International Diagnostic Interview (CIDI) epidemiological
surveys). As has been reported in the literature, differences and similarities
in rates of mental disorders were found from these comparisons, and no
satisfactory explanations seem to have been reached hitherto
(Weissman et al,
1997; Copeland et al,
1999).

In general, however, there is a trend towards comparable rates of specific
disorders among general population studies using the same case definition and
case identification instruments. For example, the point prevalence rates for
ICD-9 depression (296.2/300.4) across seven communities using Present State
Examination—CATEGO ranged from 4.6 in Santander, Spain and two cities in
Finland to 7.4% in Athens, Greece. The lifetime prevalences for DSM-III major
depression using DIS were similar in the US Epidemiologic Catchment Area (ECA)
study (4.4%), Puerto Rico (4.6%) and Seoul, Korea (3.4%), but with
exceptionally lower rates in Taiwan (0.9-1.7%)
(Smith & Weissman,
1992).

The lower rates of most disorders in the DIS survey in Taiwan compared with
data from other countries cannot be explained by differences in case
definition, rural—urban distribution of study subjects or somatisation
tendency (Weissman et al,
1997). However, a recent community study among the elderly in
Taiwan using the GMS found a 1-month prevalence rate of 21.7% for all
depressive disorders, which is close to the figures from GMS studies in New
York (16.2%), London (19.4%) and Munich (23.6%)
(Tsang, 2000). Rates of
DSM-III-R major depression among consecutive suicides using psychological
autopsy was reported to be 87% in the East Taiwan Suicide Study, which is also
close to other studies (Cheng,
1995).

The evidence gathered, therefore, seems to suggest that differences in
case-finding methods may largely account for the differences in rates of
mental disorders in previous work employing the same case definition and
diagnostic system. There is no sound evidence at present to support a real
difference in major psychiatric disorders across cultures and societies.
Furthermore, cases identified by clinical interview differed considerably from
cases identified by lay-interview among the same study population
(Anthony et al, 1985).
Because self-report and clinician-rated approaches give different information
in Western countries, the implications of this for cross-cultural studies
needs to be and has yet to be considered. Furthermore, more detailed formal
reanalyses of the existing data may not be warranted because of differences in
the measurement design and sampling between studies.

The inclusion of most culture-specific disorders in the annex of ICD-10-DCR
with suggested ICD-10 codes may serve as useful reference for future studies
to clarify their relationships. It might be suggested further that
investigators with such intention should apply standardised, cross-culturally
comparable clinical interviews to reach satisfactory diagnoses.

Because it is argued that culture-specific disorders might have come mainly
from culture-specific illness behaviour rather than specific psychopathology,
a new classification system for illness behaviour found in different cultures
may be desirable in future editions of the ICD. Such a new system will be able
to cover most culture-specific disorders around the world, perhaps also
including anorexia nervosa and others primarily identified in Western
societies. It might add useful knowledge for preventive measures and
eventually clinical services.

Case identification

The standardised diagnostic interview

In a standardised diagnostic interview, clinically significant symptoms are
identified and diagnosis is then made according to the diagnostic criteria
applied, as with ICD-10 or DSM-IV. However, the choice of fully structured or
semi-structured interview for case identification in psychiatric research is a
major issue that seems to have been much less emphasised hitherto
(Brugha et al,
1999a). Using the former, only the self-reported presence
or absence of symptoms can be obtained. It has been argued recently that
self-reported symptoms alone are insufficient for case identification, and
that illness (symptom) severity and duration, comorbidity and associated
functional impairment also should be assessed
(Regier et al, 1998).
It would be very difficult, if not impossible, to perform such assessment with
a fully structured interview, particularly if it were conducted by
lay-interviewers lacking enough medical background. The reliability and
validity of semi-structured clinical interviews conducted by lay-interviewers
still await further examination (Brugha
et al, 1999b).

These issues are certainly relevant to researchers in non-Western countries
where both structured and semi-structured interviews have been used. The
development of cross-culturally comparable diagnostic interviews, yet to be
fully achieved, will not only facilitate cross-cultural comparability in
epidemiological studies of mental disorders but also serve as the optimal
instrument to validate fully structured lay-interviews and screening
tools.

One important step in developing such clinical interviews is to ensure the
semantic or psycholinguistic equivalence of psychiatric symptoms across
cultures (Cox, 1977;
Cheng, 1989). Only if research
psychiatrists from East and West can work together as a team to develop such
instruments will this issue be resolved satisfactorily. All the symptom items
considered to have culture-specific expression can then be brought out for
thorough direct discussion based on real case examples videotaped with
transcriptions in different languages. It is believed that anthropologically
oriented researchers will make a substantial contribution to this
endeavour.

In the International Pilot Study of Schizophrenia, such an exercise was
carried out with the Present State Examination - 6th edn, largely focused on
psychoses (World Health Organization,
1973). There is therefore an urgent need to conduct similar
exercises for the non-psychotic depressive and neurotic symptoms, as well as
for the behaviours and symptoms regarded as salient in substance use and
organic mental disorders. In Taiwan, Cheng and his SCAN (Schedules for
Clinical Assessment in Neuropsychiatry) research group have begun to work in
this way in collaboration with US/UK SCAN experts over the past few years
(Cheng et al,
2001).

Interviewer bias

The problem of professional interviewer bias was well reported in the early
1970s. It could be argued that in developing nations where psychoses rather
than neurotic disorders have long been highlighted the much lower reported
rates of depressive illness and neurotic disorders might be at least in part
derived from an underdiagnosis of such disorders with a stereotyped diagnostic
practice. This kind of underdiagnosis can only be investigated and perhaps
resolved when investigators in developing nations use cross-culturally
comparable standardised clinical interviews to conduct interrater reliability
exercises involving psychiatrists from East and West, not only for psychotic
but also for depressive and neurotic symptoms
(Cheng et al,
2001).

The validity of lay-interviews and potential lay-interviewer bias in
large-scale general population surveys have been investigated in DIS and CIDI
surveys (e.g. Anthony et al,
1985; Kessler et al,
1997; Brugha et al,
1999a). The lay-interviewer bias also requires careful
examination in developing nations against independent clinical reappraisal, a
task that has not been well conducted hitherto, partly because of the lack of
cross-culturally comparable standardised clinical interviews.

Interviewee bias

Interviewee bias is another problem being investigated in CIDI surveys
(Kessler et al,
1997). In developing nations, experienced lay-interviewers are
scarce. People there with limited knowledge and strong social stigma about
mental illness expect to get medical help from a physician only for their
somatic symptoms. Hence, the detection of psychiatric symptoms among
non-psychiatric patients and community respondents in developing nations by
lay-interviews may encounter a more serious problem of underreporting.

This problem will certainly impose great difficulty when conducting
large-scale epidemiological surveys in developing nations, where a serious
shortage of mental health professionals has long existed. A plausible solution
for investigators is to apply a two-stage case-finding strategy, with a brief
screening tool for the first stage and clinical interview by professionals for
the second stage. This strategy can save substantial time, money and
professional resources while providing highly accurate data for prevalence
estimation, clinical investigation and assessment of risk factors. It calls
for the training of lay-interviewers with a high level of quality control, and
the development of cross-culturally reliable and valid screening tools for use
in the first stage (Mari et al,
1988). Moreover, locally based mental health professionals using a
semi-structured interview with satisfactory cross-cultural reliability are
essential at the second stage because they are fully attuned to local modes of
self-expression.

CONCLUSIONS

“Comparative psychiatry must lean to the etic rather than to the emic
position, since with the emic, no comparisons are usually possible.”

This statement might be reformulated today as ‘a combined etic/emic
approach to comparative psychiatry is feasible if a standardised diagnostic
interview that has incorporated psycholinguistic equivalents from different
cultures is used’.

In conclusion, cultural variation in mental health is mainly in the
presenting features rather than in the nature and frequency of the underlying
neuropsychiatric impairments and disorders. The finding of culture-general
diagnostic entities is of great importance because it may greatly facilitate
cross-cultural studies in aetiology, risk factors and preventive measures.
Very simply, the benefits of evidence-based psychiatry in one part of the
world can be applied elsewhere for the benefit of all.

Acknowledgments

The author would like to thank Professors T. S. Brugha, B. Cooper and G.
Parker for their invaluable comments on the first draft of this manuscript,
and the support of Professor A. H. Mann, Institute of Psychiatry, London,
during the preparation of this work.